Apparatus for cutting tobacco



Nov. 28, 1967 u. ELSNER APPARATUS FOR CUTTING TOBACCO 5 Sheets-Sheet 1 Filed Nov. 5, 1965 Nov. 28, 1967 u. ELSNER APPARATUS FOR CUTTING TOBACCO Filed Nov. 5, 1965 5 Sheets-Sheet 2 n Z w 1 w L v W \F mm L 7 C m w yM AK RN m E NW w 2 m Q Q m NW mm aw Nov. 28, 1967 u. ELSNER 3,354,921

APPARATUS FOR CUTTING TOBACCO Inventor: ZLM $154M Nov. 28, 1967 u. ELSNER APPARATUS FOR CUTTING TOBACCO 5 Sheets-Sheet 4 Filed Nov. 5, 1965 X? KmN mww mw RN I I l I l I J wfl l l ll fl l n u FM M H Tuuri a L w Inventor: [La E11? Nov. 28, 1967 u. ELSNER 3,354,921

APPARATUS FOR CUTTING TOBACCO Filed Nov. 5, 1965 5 Sheets-Sheet 5 Inventor: ZLW- 5&W

United States Patent 3,354,921 APPARATUS FOR CUTTING TOBACCO Uwe Elsner, Hamburg-Bramfeld, Germany, assignor to Hauni-Werke Korber & Co. Kg., Hamhurg-Bergedorf, Germany Filed Nov. 3, 1965, Ser. No. 506,160 Claims priority, application Great Britain, June 19, 1964, 25,456/64; Nov. 6, 1964, 45,433/ 64 20 Claims. (Cl. 146-120) This is a continuation-in-part of my copending application Ser. No. 464,997 filed on June 18, 1965.

The present invention relates to an apparatus for cutting tobacco and similar fibrous materials. More particularly, the invention relates to improvements. in an apparatus which may be used for shredding superimposed tobacco leaves. Still more particularly, the invention relates to an apparatus which can be used for subdividing a continuous cake of superimposed and strongly compacted tobacco leaves into straight or tortuous shreds for use in the manufacture of cigarettes and similar smokers articles.

It is an important object of the present invention to provide a very simple, rugged and compact cutting or shredding apparatus which is constructed and assembled in such a way that the likelihood of admixing liquid or incrustated tobacco juice to the shredded material or of permitting such juice to penetrate into the moving parts of the apparatus is reduced to a minimum.

Another object of the invention is to provide an apparatus of the just outlined characteristics wherein the cutting edges of comminuting knives may be sharpened and cleaned in a very simple and eflicient manner.

A further object of the invention is to provide a novel arrangement for maintaining one or more comminuting knives in an optimum position of inclination with reference to the material to be cut and to effect such positioning of the knife or knives by resorting to a single prime mover which, in addition to maintaining the knives in desired position, also causes the knives to travel in a predetermined path and to thereby comminute the tobacco leaves at a rate required in a mass-producing tobacco processing plant.'

An additional object of the instant invention is to provide a novel automatic feed for the knives of a tobacco shredding apparatus and to construct the feed in such a way that the knives are moved or shifted with reference to their holders at the same rate at which their cutting edges wear away in response to the sharpening action of a grinding device.

Still another object of .the invention is to provide a shredding apparatus wherein the knives may be inserted, clamped, adjusted and/or removed in a very simple and time-saving manner.

A further object of the invention is to provide an apparatus of the just outlined characteristics wherein the feed of knives takes place in automatic response to travel of knives in a predetermined path which leads the cutting edges into repeated engagement with a mass of stacked tobacco leaves.

A concomitant object of the invention is to provide a shredding apparatus wherein the freshly comminuted material may descend by gravity feed and wherein such material cannot interfere with the operation of moving parts.

Briefly stated, one feature of my invention resides in the provision of an apparatus for cutting or shredding tobacco leaves or similar materials. In its simplest form, the apparatus comprises a stationary frame, a rotor assembly mounted in the frame for rotation about a first axis, a knife holder mounted in and rockable with reference to the rotor assembly about a second axis which is at least nearly parallel to the first axis, means for rocking the holder in response to rotation of the assembly about the first axis, a knife detachably mounted on the holder and having an elongated cutting edge which orbits in an endless path in response to rotation of the assembly, grinding means adjacent to the first portion of the endless path for sharpening the cutting edge, a feed for changing the position of the knife with reference to the holder in response to rocking of the holder so as to compensate for Wear in response to sharpening by the grinding means, and means for advancing the material to be cut into a second portion of the endless path so that such material is severed by the cutting edge.

In accordance with another important feature of my invention, the holder is rocked in such a way that its inclination with reference to the direction in which the material to be cut is advanced into the second portion of the endless path remains unchanged. The grinding means sharpens that side of the knife which faces away from the material to be cut and the inclination of the holder is selected in such a way that the other side of the knife (namely, that side which faces the material to be cut) remains spaced from the front face of such material.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved cutting or shredding apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a transverse vertical section through a shredding apparatus which embodies one form of my invention, the section being taken in the direction of arrows as seen from the line II of FIG. 2;

FIG. 2 is a section substantially as seen in the direction of arrows from the line II-II of FIG. 1;

FIG. 3 is an enlarged transverse vertical section through the transmission housing of a knife holder;

FIG. 4 is a horizontal section substantially as seen in the direction of arrows from the line IVIV of FIG. 3;

FIG. 5 is a fragmentary end elevational view substantially as seen in the direction of arrow V in FIG. 3;

FIG. 6 is a transverse section through a knife holder substantially as seen in the direction of arrows from the line VI-VI of FIG. 5

FIG. 7 is a section substantially as seen in the direction of arrows from the line VII-VII of FIG. 5 and illustrates the mechanism which clamps the knife to the rev spective holder, the clamping mechanism being shown in operative position;

FIG. 8 illustrates the clamping mechanism in inoperative position;

FIG. 9 is a section substantially as seen in the direction of arrows from the line IX-IX of FIG. 7; and

FIG. 10 is a section susbtantially as seen in the direction of arrows from the line XX of FIG. 9.

Referring first to FIGS. 1 and 2, the shredding apparatus therein shown comprises a substantially U-shaped frame or stator 1 which supports two rotary conveying and compressing rolls 2, 4, a mouthpiece 5 which is located immediately downstream of the gap defined by the conveying rolls 2, 4, a grinding device 7, and a rotor assembly RA.

The rotor assembly RA comprises a horizontal drive shaft 11 which is driven by a prime mover through a pulley 12, and a pair of axially spaced disk-shaped carriers 8, 10 for an annulus of six equidistant knife holders or supports 15. Each holder 15 supports a detachable knife 14 having an elongated cutting edge 14a. The carrier 8 supports six hollow rotary transmission housings 17, and the carrier supports an equal number of trunnions 24. The parts 17, 24 are respectively mounted in roller bearings 25 and 26. Each holder extends between one of the housings 17 and the aligned trunnion 24. The upwardly extending side walls 1a of the frame 1 are provided with annular shoulders 19 for a pair of annular antifriction bearings 18, and each of these hearings supports a guide ring 20. It will be noted that the rings 20 are eccentric with reference to the drive shaft 11, and each of these rings is adjacent to the outer side of the respective carrier 8 or 10.

The guide rings 20 are formed with axially parallel bores 21 for coupling pins 22, and each such coupling pin is eccentric with reference to the associated transmission housing 17 or trunnion 24. Disk-shaped distancing elements or spacers 33 are mounted on the right-hand set of coupling pins 22, as the parts appear in FIG. 2, and each such spacer 33 is disposed between the right-hand guide ring 20 and the respective trunnion 24.

FIGS. 3 and 5 illustrate in greater detail the means for feeding the knives 14 so as to compensate for wear on the cutting edges 14a. Such wear is due to repeated engagement of cutting edges 14a with the pot-shaped grinding wheel 39 of the grinding device 7 and also to repeated penetration of cutting edges 14a into the cake or slab 6 of compressed tobacco leaves which issues from the outlet of the mouthpiece 5. The feed for the knives 14 operates in a fully automatic way and is adjustable in order to advance the knives at the exact rate at which the cutting edges 14a wear away. The wear on the cutting edges 14a is due mainly to the grinding action of the wheel 39, and such grinding action is necessary because the cutting edges become dull in response to penetration into the leading end of the cake 6.

The just mentioned feed comprises a series of transmissions each of which is accommodated in one of the housings 17. Each such transmission comprises a gear 27 which is mounted on the respective drive pin 22 and is rotatable on an annular roller bearing 29, see FIG. 3. Each gear 27 is non-rotatably secured to the corresponding guide ring 20 by means of four screws or bolts 23, and'each such gear 27 meshes with an intermediate gear 28 which also forms part of the transmission in the respective housing 17 and is mounted on the shaft 30 of a worm 31, the latter meshing with a worm wheel 32 provided on a hollow shaft 34 mounted on a bolt 42. The shaft 34 also carriers a second worm 35 which meshes with a second worm wheel 37 provided on a shaft 38. The shaft 38 further carries a spur gear 40 which meshes with a feed gear 41 mounted on a shaft 44. The shaft 44 carries two worms 45, 47 (see FIG. 2) which mesh with worm wheels 48, 50 whose end faces are provided with pairs of shifting pins 52, 54. The pins 52, 54 may be replaced by cams or by analogous shifting elements which are capable of moving or advancing the knives 14 at the rate corresponding to the Wear on the cutting edges 14a. When the shifting pins 52. 54 are replaced by cams, the cam faces must be precision finished to insure that each thereof has an accurately determined curvature.

FIGS. 7 to 10 illustrate the manner in which the knives 14 are mounted on the respective holders 15. Each holder 15 cooperates with a clamping plate 55 which may be biased by several clamping levers 57. The levers 57 are mounted in U-shaped bearing brackets 58, and each bearing bracket 58 is non-movably accommodated in a recess 60 provided in the respective holder 15.

The arm 61 of each bearing bracket 58 supports a stub shaft 62 which is connected with an actuating lever 64. Each lever 64 comprises an eccentric projection or stud 65.

The operation of the shredding apparatus is as follows:

The conveying rolls 2, 4 are operated intermittently or continuously and strongly compress a stack of tobacco leaves so that such leaves form a cake or slab 6 which is fed into and through the mouthpiece 5 so that the forward end of the cake 6 enters the cylindrical path S defined by the cutting edges 14a of the orbiting knives 14. The ro= tor assembly RA is driven by the pulley 12 which rotates the shaft 11 and the carriers 8, 10, so that the holders 15 orbit about the axis of the shaft 11. The direction in which the rotor assembly RA rotates is indicated by an arrow P, see FIG. 1. The end portions of each holder 15 are respectively supported by one of the housing 17 and by the aligned trunnion 24.

As best shown in FIGS. 1, 2 and 3, the coupling pins 22 are eccentric with reference to the common axes of the associated parts 17, 24, and these coupling pins 22 extend into the bores 21 of the guides rings 20 which are eccentric with reference to the shaft 11. Such mounting of the coupling pins 22 causes the holders 15 to swivel or rock about the axis of the shafts 44 with reference to the rotating carriers 8, 10 whereby such rocking movement effects that the inclination of planes in which the knives 14 are mounted remains unchanged despite the fact that the holders 15 and the knives 14 orbit about the axis of the shaft 11. During such orbiting movement, the cutting edges 14a travel in the aforementioned endless cylindrical path S, and the inclination of the knives 14 is preferably such that their planes remain normal or substantially normal to the general plane of the tobacco cake 6, i.e., with reference to a horizontal plane because the cake 6 is shown as being advanced in a horizontal path. The axis of each shaft 44 is parallel to the respective cutting edge 14a and to the axis of the shaft 11.

During travel past the outlet of the mouthpiece 5, the rear side 36 of each knife 14 (see FIG. 6) faces the mouthpiece and the cutting edge 14a removes from the cake 6 a strip or layer 9 which contains a plurality of superimposed tobacco shreds. The rear side 36 remains spaced from the front end face 13 of the cake 6, see FIG. 1.

The cutting edge 14a of that knife 14 which has just removed a fresh layer 9 of compressed tobacco shreds thereupon advances toward and its front side 16 comes in contact with the wheel 39 of the grinding device 7.

Automatic feed of the knives 14 is initiated by the gears 27 which are mounted on the corresponding coupling pins 22 and are attached to the corresponding guide ring 29 (by means of the aforementioned screws or bolts 23). These gears 27 cause the corresponding transmission housings 17 to rotate about their own axes, always through angles of predetermined magnitude. During rotation of the housings 17, the intermediate gears 28 which mesh with the respective gears 27 cause the shafts 30 and worms 31 to rotate. Each worm 31 then rotates the respective worm wheel 32, the respective shaft 34 and the respective worm 35. The worms 35 rotate the associated worm wheels 37 and shaft 38 whereby the gears 40 drive the gears 41 and shafts 44. The threads of worms 45, 47 on each shaft 44 are of the opposite lead so that the worm wheels 48, 50 are driven in opposite directions. The shifting pins 52, 54 thereby advance the respective knife 14 with reference to the corresponding holder 15, always through such a distance as is necessary to compensate for the wear on the cutting edge 14a in response to engagement with the grinding Wheel 39.

When a fresh knife 14 is introduced into the holder 15, the rear edge face of the knife is engaged by the studs 52, see the top part of FIG. 5. Once the knife 14 has been advanced by a predetermined distance, its rear edge face is engaged by both pairs of studs 52, 54 (see the positions 52', 54 in FIG. 5). If the knife 14 is advanced still further, its rear edge face is engaged solely by the studs 54 (see the positions 52", 54" in FIG. 5).

FIGS. 7 to 10 show that the actuating lever 64 may be manipulated to move the clamping lever 57 away from or toward the respective clamping plate 55 whereby the plate 55 may move away from the corresponding knife 14 (FIG. 8) or is forced against the knife (FIG. 7).

The arrow 67 indicates the direction in which the actuating lever 64 is rocked in order to move the plate 55 to clamping position, and the arrow 68 indicates the opposite direction in which the lever 64 is moved in order to disengage the plate 55 from the knife 14. When the actuating lever 64 is moved in the direction indicated by the arrow 67, the clamping lever 57 is moved from a deadcenter position and thereby presses the clamping plate 55 against the corresponding knife 14. When the lever 64 is rocked in the direction indicated by the arrow 68, the pin 65 is moved through an angle of 90 degrees (and upwardly, as viewed in FIG. 8) to thereby terminate the clamping action of the plate 55.

The rear sides 36 of the edges 14a on the knives 14 may be of tortuous (undulate or zig-zag) shape as disclosed in my aforementioned application Ser. No. 464,997. However, it is equally within the purview of my present invention to provide the knives 14 with straight cutting edges.

The grinding device 7 reciprocates in the longitudinal direction of the cutting edges 14a (see the double-headed arrow 7a in FIG. 2) in a manner as disclosed in the application Ser. No. 464,997. The device 7 is guided by ways 7b provided on the frame 1. It will be noted that the grinding wheel 39 engages the front sides 16 of the cutting edges 14a, i.e., such sides which face away from the outlet of the mouthpiece S. The wheel 39 also performs a cleaning action by removing from the cutting edges 14a tobacco juice which deposits on the front sides 16 while the cutting edges sever the cake 6.

A very important prerequisite for satisfactory operation of a tobacco shredding apparatus is that the knives must engage the cake 6 while being held in a predetermined angular position with reference to the plane of the cake. The angle 'must be such that the front end face 13 of the cake 6 should not press against the rear side 36 of the knife 14, i.e., that the cake should not rub against the knife during and immediately following the completion of a cutting action. Also, the freshly removed layer 9 should be free to descend by gravity without being entrained by the knife because the duration and extent of contact between the knife and the material to be out should be reduced to a minimum. This is important because the knife is likely to be coated with juice if it remains in longer-lasting contact with the tobacco leaves.

In many heretofore known shredding apparatus, the inclination of knives changes all the time while the knives orbit about a fixed axis. This is due to the fact that the knives are rigidly mounted in the rotor assembly and such mounting results in deposition of tobacco juice on that side of the knife which faces away from the tobacco cake. The juice hardens and forms a crust which falls into the apparatus or into the mass of shredded tobacco. In such conventional apparatus, the grinding device treats the rear sides of the knives, i.e., such sides (corresponding to the-side 36 shown in FIG. 6) which face the cake 6 during cutting.

The apparatus of my present invention overcomes the above enumerated drawbacks of conventional apparatus by the simple expedient of mounting the knife holders 15 in such a way that they are caused to rock or swivel while orbiting about the axis of the drive shaft 11. The rocking or swiveling motion i fully controlled in such a way that the inclination of the planes in which the knives 14 are located remains unchanged or substantially unchanged. In order to avoid uncontrolled wobbling, the axes of aligned coupling pins 22 and the axes of the shafts 44 are preferably parallel to the axis of the shaft 11 and to the longitudinal directions of the cutting edges 14a. The forwardly extending lower edge portion a of the mouthpiece 5 serves as a counterknife and cooperates with successive cutting edges 14a to form a clean cut across the leading end of the cake 6. FIG. 1 shows clearly that the rear side 36 of that knife 14 whose cutting edge 14:: cooperates with the counterknife 5a remains spaced from the front face 13 of the cake 6 so that the rear side 36 is not likely to be smudged with tobacco juice. As stated before, the wheel 39 removes material from the front side 16 of the knife 14 and simultaneously removes any traces of tobacco juice which might have accumulated on the knife during penetration through the cake 6. In this way, I prevent liquid or incrustated tobacco juice from falling into the mass of freshly shredded tobacco leaves. It will be seen that an important feature of my invention resides in such mounting of the knives 14 and grinding device 7 that the wheel 39 sharpens the front sides 16, rather than the rear sides 36, of the cutting edges 14a. In other words, the wheel 39 treats that side of each knift 14 which faces away from the front face 13 of the cake 6.

My aforementioned copending application Ser. No. 464,997 discloses several embodiments of knives whose rear sides (corresponding to the rear side 36 of the knife 14 shown in FIG. 6) are provided with alternating ribs and grooves so that the cutting edge assumes a tortuous (undulate or zig-zag) shape. The grinding device treats the front sides of the knives in the same way as described in connection with the grinding device 7 of FIGS. 1 and 2. Since the front sides 16 of the knives 14 may remain flat, the grinding device 7 can be equipped with a simple grinding wheel 39. The mouthpiece 5 is preferably located in a zone which is close to the lowermost portion of the rotor assembly RA so that the parts of the rotor assembly are even less likely to be contaminated by liquid or incrustated tobacco juice and/or by flying shreds of comminuted tobacco leaves.

The concave right-hand end face of the mouthpiece 5 (as viewed in FIG. 1) has a curvature which corresponds to the curvature of the cylindrical path S defined by the cutting edges 14a when the rotor assembly RA is set in motion. This is of advantage because such concave end face of the mouthpiece 5 can be readily reground, without resorting to complicated grinding patterns, whenever the counterknife 5a requires rehoning.

An important advantage of the rotor assembly RA with two axially spaced carriers 8, It) is that freshly comminuted shreds of tobacco leaves have ample room to descend by gravity without in any way interfering with movements of such parts which are mounted on the rotor assembly. A single prime mover (e.g., a-motor which drives the pulley 12) sufiices to rotate the assembly RA, to rock the knife holders 15, and to feed the knives 14 relative to the holders at the rate corresponding to wear upon the cutting edges 14a. The same drive may be used to rotate the conveying rolls 2 and 4. Due to the fact that the diameters of the housings 17 and trunnions 24 equal or approximate the width (i.e, the maximum transverse dimensions) of the knife holders 15, the parts 17, 24 can effectively oppose any unbalance caused by the holders 15 during orbiting about the axis of the shaft 11.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is:

1. An apparatus for cutting tobacco and similar materials, comprising a frame; a rotor assembly mounted in said frame for rotation about a first axis; a knife holder mounted in and rockable with reference to said assembly about a second axis which is at least nearly parallel to said first axis; rocking means for rocking said holder in response to rotation of and with reference to said assembly; a knife mounted on said holder and having an elongated cutting edge which orbits in an endless path in response to rotation of said assembly; grinding means adjacent to a first portion of said path for sharpening said cutting edge; a feed for changing the position of said knife with reference to said holder in response to rocking of said holder so as to compensate for wear in response to sharpening by said grinding means; and conveying means for advancing the material to be cut into a second portion of said path so that such material is severed by said cutting edge.

2. An apparatus as set forth in claim 1, wherein said cutting edge is substantially parallel with said second axis.

3. An apparatus as set forth in claim 1, wherein said conveying means includes means for compressing the material and further comprising a mouthpiece for guiding the thus compressed material into the second portion of said path, said mouthpiece comprising a counterknife which cooperates with said first named knife when said cutting edge travels in the second portion of said path.

4. An apparatus as set forth in claim 1, wherein said rocking means is arranged to maintain said knife in a predetermined position of inclination with reference to the direction in which the material is advanced into the second portion of said path.

5. An apparatus as set forth in claim 1, wherein said rotor assembly comprises a pair of axially spaced carriers, said holder and said knife being disposed therebetween and said holder having end portions rockably supported by said carriers.

6. An apparatus as set forth in claim 1, further comprising a plurality of additional holders mounted in said assembly, said holders together forming an annulus of equidistant holders which surrounds said first axis, and rocking means for each of said additional holders, each of said rocking means being operative in response to rotation of said assembly.

7. An apparatus as set forth in claim 1, wherein said rocking means comprises an eccentric coupling member extending from said rotor assembly and guide means connected to said coupling member and rotatably supported by said frame.

8. An apparatus as set forth in claim 7, wherein said guide means comprises a ring whose axis is spaced from and is parallel to said first axis.

9. An apparatus as set forth in claim 1, wherein said rotor assembly comprises a pair of axially spaced carriers and wherein said holder extends between said carriers, said rocking means comprising a transmission housing supportingly connected with one end of said holder and rotatably mounted in one of said carriers.

10. An apparatus as set forth in claim 9, wherein said rocking means further comprises a trunnion supportingly connected with the other end of said holder and rotatably mounted in the other carrier, said trunnion being coaxial with said housing.

11. An apparatus as set forth in claim 10, wherein the diameters of said housing and said trunnion approximate the maximum transverse dimension of said holder,

12. An apparatus as set forth in claim 10, further comprising a plurality of additional knife holders and rocking means therefor, the transmission housings and trunnions of said rocking means being respectively equidistant from each other.

13. An apparatus as set forth in claim 1, wherein said feed receives motion from said rocking means.

14. An apparatus as set forth in claim 13, wherein said rocking means comprises a rotary guide member mounted on said frame adjacent and eccentric with reference to said assembly, a housing rotatably mounted in said assembly and supportingly connected with said holder, an eccentric coupling member connecting said housing with said guide member, and a gear rotatably mounted on said coupling member, said gear being arranged to transmit motion to said feed in response to rocking of said holder.

15. An apparatus as set forth in claim 14, wherein said feed comprises a train of motion transmitting elements and shifting means driven by said elements and engaging said knife to shift the same with reference to said holder in response to rotation of said gear.

16. An apparatus as set forth in claim 1, further comprising releasable clamping means for securing said knife to said holder, said clamping means comprising a clamping plate and a clamping lever supported by said holder and movable into engagement with said plate to thereby urge the plate against said knife.

17. An apparatus as set forth in claim 16, wherein said clamping means further comprises an actuating lever mounted on said holder and arranged to move said clamping lever into and out of engagement with said plate.

18. An apparatus as set forth in claim 1, wherein said knife has a rear side which faces the material and a front side and wherein said grinding means is arranged to engage the front side of said knife.

19. An apparatus as set forth in claim 18, wherein said rocking means is arranged to maintain said knife in such position of inclination that, while the cutting edge moves in the second portion of said path, said rear side remains spaced from the front face of the material which is being severed by said cutting edge.

20. An apparatus as set forth in claim 18, wherein said cutting edge is of tortuous shape.

References Cited UNITED STATES PATENTS 345,695 7/1886 Heebner 83-327 X 1,647,694 11/1927 Hawkins 131-14 2,751,949 6/ 1956 Ritscher 146-117 3,003,530 10/1961 Urschel et a1 83-327 X 3,117,602 1/ 1964 Gamberini 146-119 WILLIAM W. DYER, 111., Primary Examiner. W, GRAYDON ABERCROMBIE, Examiner, 

1. AN APPARATUS FOR CUTTING TOBACCO AND SIMILAR MATERIALS, COMPRISING A FRAME; A ROTOR ASSEMBLY MOUNTED IN SAID FRAME FOR ROTATION ABOUT A FIRST AXIS; A KNIFE HOLDER MOUNTED IN AND ROCKABLE WITH REFERENCE TO SAID ASSEMBLY ABOUT A SECOND AXIS WHICH IS AT LEAST NEARLY PARALLEL TO SAID FIRST AXIS; ROCKING MEANS FOR ROCKING SAID HOLDER IN RESPONSE TO ROTATION OF AND WITH REFERENCE TO SAID ASSEMBLY; A KNIFE MOUNTED ON SAID HOLDER AND HAVING AN ELONGATED CUTTING EDGE WHICH ORBITS IN AN ENDLESS PATH IN RESPONSE TO ROTATION OF SAID ASSEMBLY; GRINDING MEANS ADJACENT TO A FIRST PORTION OF SAID PATH FOR SHARPENING SAID CUTTING EDGE; A FEED FOR CHANGING THE POSITION OF SAID KNIFE WITH REFERENCE TO SAID HOLDER IN RESPONSE TO ROCKING OF SAID HOLDER SO AS TO COMPENSATE FOR WEAR IN RESPONSE TO SHARPENING BY SAID GRINDING MEANS; AND CONVEYING MEANS FOR ADVANCING THE MATERIAL TO BE CUT INTO A SECONG PORTION OF SAID PATH SO THAT SUCH MATERIAL IS SEVERED BY SAID CUTTING EDGE. 